(465e) Design of Methane Hydrate Decomposition Process Combined with Conventional LNG Receiving Terminal

Recently, transportation of natural gas (NG) in the form of natural gas hydrate (NGH) is in interest because of its economic feasibility and safety. It also gives advantage of diversification of NG transport and import. Nevertheless, there is no study of converting NGH to pipeline natural gas (PNG), which is the most common distribution method in domestic transport.

In this research, the process of converting MH to PNG combined with existing LNG receiving terminal is designed. It is assumed that NG is transported in MH dry pellet form, composed of CH4 and H2O in the proportion of 1:6. Storage tank of MH is assumed to be 1 bar and -20 °C.

First, MH decomposition process (regasification process) is designed. Sensitivity analysis of the process using design variables, i.e. decomposition temperature, is performed. Gas stream from decomposed MH goes through the glycol dehydration unit to meet water content specification of PNG (less than 120 ppm). Then, the dehydrated gas is compressed in multi-stages for use as PNG while cryogenic energy of LNG is integrated in the process to cool down the compressed gas stream. Assuming fixed PNG send out rate, optimal quantities of LNG and MH are determined for minimum operating cost.